Brian McLean works at animation studio LAIKA, and was Facial Structure Supervisor on the company's Oscar-nominated 2009 feature "Coraline."

It was on the latter that he became central to exploring for the company how modern technology could bolster what was being created by hand, and worked on the company's Rapid Prototyping (RP) advances.

He now oversees LAIKA's RP department.

Q: For those who don't know - what exactly is Rapid Prototyping?

A: It is terminology used to describe a process in which you can go from computer designed object to a three-dimensional, physical object. LAIKA uses 2 different type of Rapid Prototyping machines (commonly called 3D printers):

3D Systems z650 color printers. Powder based printers that drag a very thin layer of powder (plaster and polymer) on a bed and spray CYMK colored binder (or colored glue) This colored binder hardens sections of powder and then another layer of powdered is dragged across the bed and the process is repeated over and over until eventually you have a 3D part buried in powder. When you remove the 3D part it is covered in unhardened powder, once this powder is blow away you are left with a very fragile, but color printed 3D object. To strengthen the part it is dipped into a thin super glue which absorbs into the part and gives it strength. This process allows us to design and animate thousands of faces that are printed out in full color.

Objet Polyjet Printers. Resin based printers that spray a very thin layer of liquid resin and water soluble liquid support onto a bed. A UV light hardens the resin and support, the tray lowers and another layer of liquid is sprayed and hardened by UV light. This process is repeated over and over again until a 3D object is formed. When you remove the 3D part it is covered in water soluble support material, once this support material is washed away you are strong plastic object. This process allows use to design and engineer tiny mechanically functioning parts that can be used in anything from puppet heads to props.

Q: Do they emerge fully formed from the git-go?

A: Not quite, each technology requires some clean up of the 3D printed parts.

We also have to do a lot of quality control and testing. As advanced as these machines are they were never designed to do what we are using them form. Every face is tested for color consistency and dimensional accuracy.

Often faces are discarded because they do not meet the required standards.

Q: How has the technology been advanced since Coraline?

A: With "Coraline," LAIKA became the first company to do a feature-length movie using RP, specifically for replacement faces printed on a 3D Printer. It was beautifully articulated. But LAIKA wanted to continue to push the level of performance that a stop-motion puppet could give, and to modernize the process.

Now, with ParaNorman, we have made the first stop-motion movie that uses a 3D Color Printer. The technique is similar, but what the 3D Color Printer affords you to do is to build color into the model. So it's a big move forward.

Q: Can you give some comparisons?

A: Coraline had well over 200,000 potential facial expressions, and Norman has 1.5 million. Norman's friend Neil has hundreds of freckles on his face - Coraline had 10.

Q: Some things you can't quantify by numbers. What's pleased you in terms of the craft?

A: With the color printer we were able to not only give the characters a huge emotional range but we were able to give them realistic looking skin with wonderfully subtle detail.

The way that the 3D color printer prints an object means that the color is not just on the exterior surface but is actually colored deep into the surface. The by-product of this is that it gives each character's face a depth and realistic skin quality that was previously impossible to achieve in replacement animation. Norman's ear were also printed on the 3D printer and are a good example of this is subsurface scattering technique. Norman's ears are not only translucent but have a depth to them that makes it feel like they are made of skin and cartilage, when in fact they are printed on a color printer!

Q: How does RP help the animators perform the characters?

A: Working with the Directors, Brad Schiff; Animation Supervisor and Peg Serena, Facial Animator Supervisor, CG animators build/animate every expression and emotion a character will need. The CG animator is not only defining the character facial performance but they are also giving them a personality and individuality. From phonemes to a smile mouth, a screaming mouth, and all the movements in-between - they're digital sculptors creating a library of facial expressions. Once printed these faces live in a face library. Tim Yates, Lead Face Librarian and his team tests each face to make sure it is ready for the stage and then store it amongst thousands of other faces.

When a stop motion animator is ready to go to set to animate a puppet then meet with a specialized Facial Animator who helps them pick the perfect faces for their shot. Not only getting the lip sync exact (matching the movement to syllables; "ooh, "aah," "ee," "vvv," and so on) but making sure the character has the right emotion. Once approved the Face Library is notified what faces were chosen and then just those faces are tested again and delivered to the stop motion animator. The stop motion animator then has an Xsheet which tells him/her exactly what frame they need what face. This process allows the stop motion animator to really focus on the body performance knowing that the facial performance that they had already pre-vized is approved is taken care of.

Q: How big is the department? Do they work closely with the rest of LAIKA?

A: The RP Department is over 40 people, encompassing CG experts, engineers, model makers, painters and sculptors. There are Six 3D printers (Four-3D Color Printers and Two-3D plastic printers) 3D printers are just a tool that allow these extremely talented artist and technicians artists enhance their creative process.

Q: What does the department do that we won't necessarily perceive on-screen?

A: We do a lot of design and engineering that is unperceivable to the audience. Each replacement face character has an elaborate registration system that is custom designed based on each unique character design. The registration system consists of magnets and specially designed surfaces that allow each face to register in exactly the same spot. We also have to design and engineer the mechanism that moves the eye ball and eye lids.

Each eye ball and lid are able to be individually tensioned giving the stop motion animator absolute control over their movements. Normans head as an example is made up of over 78 individual parts, but when the audience see him the can only see 9.

Q: Are there any color limitations with 3D printing?

A: In the beginning we thought there were a lot of color limitations. Tory Bryant, Lead Texture painter as broken down so many perceivable barriers with these machines. She has been able to achieve far more of a color range than anyone thought (including the printer manufacture) One technique that she uses to fool the machine into printing color that would normally be out of it color gamut is "cross hatching".

By combining two colors that the machine can print in different patterns she is able to have the colors "mix" on the surface and great a new color.

While RP was originally conceived at LAIKA to produce replacement faces, it has grown in scope. Our department can now help out with props - such as Mitch's van, Babcock Station wagon and Sheriff Hooper's Moped. Not to mention some practical visual effects like over flowing toilets and tears.

Q: What else were you particularly proud of on ParaNorman?

A: Aside from the wonderful realistic replacement faces I am proud of being able to solve an age old issues with the replacement face character designs. Characters like Alvin and Perry having, basically, no neck would have been impossible with out the color printer.

Q: What tools of the trade do you swear by?

A: AutoDesks Maya, Zbrush and Photoshop

Q: What animation system are you most comfortable with?

A: The RP CG animators use AutoDesks Maya

Q: What facilities have you been impressed with in recent years?

A: Pixar. Great stories combined with wonderful visuals.

Q: What effect do you hope ParaNorman has on audiences?

A: ParaNorman is not only a wonderful story but it is the most advanced stop motion film of all time. I think the audience members will ultimately get so involved in the story that the will forget that they are actually watching a hand crafted stop motion movie. Only after the movie is over do they have time to think "whoa how in the world did they do that?"

To read Part 1 (Q&A with Director of Photography Tristan Oliver) click here.